The collection, which originally belonged to Hans Sachs, a Jewish dentist in Berlin, has been recovered by his son Peter and will be sold at Guernsey's Auction House.
The artists behind the depictions of everything from art to opera, propaganda and sports, include Alphonse Mucha, Jules Cheret, Gustav Klimt, Toulouse-Lautrec, Käthe Kollwitz, Max Slevogt and Max Klinger.
The original Sachs collection numbered up to 12,500 posters. The family received compensation from the German government in 1961 for about the equivalent of €500,000.
However, Peter Sachs discovered that a third of the posters were actually at the German Historical Museum in Berlin. After a legal battle, the Sachs family was given ownership.
"The collection dates back to the early 19th century and is estimated to be worth (between) $5.75 and $20.44 million," said Arlan Ettinger, president of Guernsey's Auction House. The auction will run through the weekend.